The use of objects molded from synthetic polymers has expanded rapidly in the last several decades. In particular, polyesters have widely gained acceptance for general molding applications and in the formation of fibers and films. An additional class of polymers known as the poly(ester-carbonates) has been disclosed.
For example, U.S. Pat. No. 3,169,121 discloses a class of resins comprising both carbonate and carboxylate groups in the linear chain. The resins are prepared by reacting a difunctional carboxylic acid, a dihydric phenol, and a carbonate precursor. However, the reference does not disclose the inclusion of a moiety derived from an aromatic hydroxyacid, nor does the reference disclose the preparation of a poly(ester-carbonate) which exhibits an anisotropic melt phase.
U.S. Pat. No. 4,260,731 discloses an aromatic poly(ester-polycarbonate) resin derived from a dihydroxydiaryl compound, a mixture of a terephthaloyl chloride and an isophthaloyl chloride, and phosgene. The reference does not disclose the inclusion of a moiety derived from an aromatic hydroxyacid, nor does the reference disclose or suggest the existence or the desirability of an anisotropic melt phase.
Additional disclosures of poly(ester-carbonate) include U.S. Pat. Nos. 3,053,810, 3,220,976, and 3,409,704.
Although many polyesters and poly(ester-carbonate) have mechanical properties suitable for general applications, most polyesters and poly(ester-carbonate) are not suitable for high strength service because the mechanical properties are not sufficiently high. One group of polymers that is suitable for high strength service without the use of a reinforcing agent is a new class of polymers exhibiting a general overall balance of mechanical properties substantially enhanced over previous polymers. These polymers have been described by various terms, including "liquid crystalline," "liquid crystal," "thermotropic," "mesogenic," and "anisotropic." Briefly, the polymers of this new class are thought to involve a parallel ordering of the molecular chains. The state wherein the molecules are so ordered is often referred to either as the liquid crystal state or the nematic phase of the liquid crystal state. These polymers are prepared from monomers which are generally long, flat, and fairly rigid along the long axis of the molecule and commonly have chain extending linkages that are either coaxial or parallel.
Disclosures of polyesters which exhibit melt anisotropy include (a) Polyester X7G-A Self-Reinforced Thermoplastic, by W. J. Jackson, Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics/Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1 to 4, (b) Belgian Pat. Nos. 828,935 and 828,936, (c) Dutch Pat. No. 7505551, (d) West German Nos. 2520819, 2520820, 2722120, 2834535, 2834536, and 2834537, (e) Japanese Nos. 43-223; 2132-116; 3017-692; and 3021-293, (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,093,595; 4,118,372; 4,130,545; 4,130,702; 4,146,702; 4,153,779; 4,156,070; 4,159,365; 4,161,470; 4,169,933; 4,181,792; 4,183,895; 4,184,996; 4,188,476; 4,201,856; 4,219,461; 4,224,433; 4,226,970; 4,228,218; 4,230,817; 4,232,143; 4,232,144; 4,238,598; 4,238,599; 4,238,600; 4,242,496; 4,245,082; 4,245,084; 4,247,514; 4,256,624; 4,265,802; 4,267,304; 269,965; 4,279,803; and 4,285,852; and (g) U.K. Application Nos. 2,002,404; 2,008,598A; and 2,030,158A. See also commonly assigned U.S. Ser. Nos. 91,003, filed Nov. 5, 1979 (now U.S. Pat. No. 4,337,191); 128,759, filed Mar. 10, 1980 (now U.S. Pat. No. 4,299,756); and 169,014, filed July 15, 1980 (now U.S. Pat. No. 4,337,190).
U.S. Pat. No. 4,107,143 discloses a substantially linear aromatic poly(ester-carbonate) consisting essentially of hydroxybenzoic acid unit, hydroquinone unit, and carbonate unit as well as, depending upon the circumstances, aromatic carboxylic acid unit. It is disclosed that the aromatic poly(ester-carbonate) exhibits melt anisotropy. However, the reference does not disclose the inclusion of a 6-oxy-2-naphthoyl moiety, as is required by the presently claimed invention.
Also, British Pat. No. 1,568,541 discloses an aromatic poly(ester-carbonate) which exhibits an anisotropic melt phase, but which lacks 6-oxy-2-naphthoyl moiety.
Other disclosures of poly(ester-carbonate) exhibiting an anisotropic melt phase include European Patent Application No. 8042001.0 (Publication No. 15856) and Japanese Patent Application No. 55129-420.
It is an object of the present invention to provide an improved poly(ester-carbonate) which is suited for the formation of quality molded articles, melt extruded fibers, and melt extruded films.
It is also an object of the present invention to provide an improved poly(ester-carbonate) which forms a highly tractable melt phase.
It is also an object of the present invention to provide an improved poly(ester-carbonate) which forms an anisotropic melt phase at a temperature well below its decomposition temperature and which may form quality fibers, films, and molded articles.
It is also an object of the present invention to provide an improved melt-processable poly(ester-carbonate) capable of forming an anisotropic melt phase at a temperature below approximately 400.degree. C., and preferably below approximately 350.degree. C.
It is also an object of the present invention to provide an improved melt-processable poly(ester-carbonate) which exhibits a highly advantageous combination of properties, including the ability to form an anisotropic melt phase, excellent tractability in the melt, and thermal stability.
It is a further object of the present invention to provide an improved melt-processable poly(ester-carbonate) which is capable of forming shaped articles which exhibit improved stiffness.
These and other objects, as well as the scope, nature and utilization of the present invention, will be apparent to those skilled in the art from the following detailed description.